/*
 * hostapd / RADIUS message processing
 * Copyright (c) 2002-2008, Jouni Malinen <j@w1.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Alternatively, this software may be distributed under the terms of BSD
 * license.
 *
 * See README and COPYING for more details.
 */

#include "includes.h"

#include "common.h"
#include "radius.h"
#include "md5.h"
#include "crypto.h"


static struct radius_attr_hdr *
radius_get_attr_hdr(struct radius_msg *msg, int idx)
{
        return (struct radius_attr_hdr *) (msg->buf + msg->attr_pos[idx]);
}


struct radius_msg *radius_msg_new(u8 code, u8 identifier)
{
        struct radius_msg *msg;

        msg = os_malloc(sizeof(*msg));
        if (msg == NULL)
                return NULL;

        if (radius_msg_initialize(msg, RADIUS_DEFAULT_MSG_SIZE)) {
                os_free(msg);
                return NULL;
        }

        radius_msg_set_hdr(msg, code, identifier);

        return msg;
}


int radius_msg_initialize(struct radius_msg *msg, size_t init_len)
{
        if (msg == NULL || init_len < sizeof(struct radius_hdr))
                return -1;

        os_memset(msg, 0, sizeof(*msg));
        msg->buf = os_zalloc(init_len);
        if (msg->buf == NULL)
                return -1;

        msg->buf_size = init_len;
        msg->hdr = (struct radius_hdr *) msg->buf;
        msg->buf_used = sizeof(*msg->hdr);

        msg->attr_pos =
                os_zalloc(RADIUS_DEFAULT_ATTR_COUNT * sizeof(*msg->attr_pos));
        if (msg->attr_pos == NULL) {
                os_free(msg->buf);
                msg->buf = NULL;
                msg->hdr = NULL;
                return -1;
        }

        msg->attr_size = RADIUS_DEFAULT_ATTR_COUNT;
        msg->attr_used = 0;

        return 0;
}


void radius_msg_set_hdr(struct radius_msg *msg, u8 code, u8 identifier)
{
        msg->hdr->code = code;
        msg->hdr->identifier = identifier;
}


void radius_msg_free(struct radius_msg *msg)
{
        os_free(msg->buf);
        msg->buf = NULL;
        msg->hdr = NULL;
        msg->buf_size = msg->buf_used = 0;

        os_free(msg->attr_pos);
        msg->attr_pos = NULL;
        msg->attr_size = msg->attr_used = 0;
}


static const char *radius_code_string(u8 code)
{
        switch (code) {
        case RADIUS_CODE_ACCESS_REQUEST: return "Access-Request";
        case RADIUS_CODE_ACCESS_ACCEPT: return "Access-Accept";
        case RADIUS_CODE_ACCESS_REJECT: return "Access-Reject";
        case RADIUS_CODE_ACCOUNTING_REQUEST: return "Accounting-Request";
        case RADIUS_CODE_ACCOUNTING_RESPONSE: return "Accounting-Response";
        case RADIUS_CODE_ACCESS_CHALLENGE: return "Access-Challenge";
        case RADIUS_CODE_STATUS_SERVER: return "Status-Server";
        case RADIUS_CODE_STATUS_CLIENT: return "Status-Client";
        case RADIUS_CODE_RESERVED: return "Reserved";
        default: return "?Unknown?";
        }
}


struct radius_attr_type {
        u8 type;
        char *name;
        enum {
                RADIUS_ATTR_UNDIST, RADIUS_ATTR_TEXT, RADIUS_ATTR_IP,
                RADIUS_ATTR_HEXDUMP, RADIUS_ATTR_INT32, RADIUS_ATTR_IPV6
        } data_type;
};

static struct radius_attr_type radius_attrs[] =
{
        { RADIUS_ATTR_USER_NAME, "User-Name", RADIUS_ATTR_TEXT },
        { RADIUS_ATTR_USER_PASSWORD, "User-Password", RADIUS_ATTR_UNDIST },
        { RADIUS_ATTR_NAS_IP_ADDRESS, "NAS-IP-Address", RADIUS_ATTR_IP },
        { RADIUS_ATTR_NAS_PORT, "NAS-Port", RADIUS_ATTR_INT32 },
        { RADIUS_ATTR_FRAMED_MTU, "Framed-MTU", RADIUS_ATTR_INT32 },
        { RADIUS_ATTR_REPLY_MESSAGE, "Reply-Message", RADIUS_ATTR_TEXT },
        { RADIUS_ATTR_STATE, "State", RADIUS_ATTR_UNDIST },
        { RADIUS_ATTR_CLASS, "Class", RADIUS_ATTR_UNDIST },
        { RADIUS_ATTR_VENDOR_SPECIFIC, "Vendor-Specific", RADIUS_ATTR_UNDIST },
        { RADIUS_ATTR_SESSION_TIMEOUT, "Session-Timeout", RADIUS_ATTR_INT32 },
        { RADIUS_ATTR_IDLE_TIMEOUT, "Idle-Timeout", RADIUS_ATTR_INT32 },
        { RADIUS_ATTR_TERMINATION_ACTION, "Termination-Action",
          RADIUS_ATTR_INT32 },
        { RADIUS_ATTR_CALLED_STATION_ID, "Called-Station-Id",
          RADIUS_ATTR_TEXT },
        { RADIUS_ATTR_CALLING_STATION_ID, "Calling-Station-Id",
          RADIUS_ATTR_TEXT },
        { RADIUS_ATTR_NAS_IDENTIFIER, "NAS-Identifier", RADIUS_ATTR_TEXT },
        { RADIUS_ATTR_PROXY_STATE, "Proxy-State", RADIUS_ATTR_UNDIST },
        { RADIUS_ATTR_ACCT_STATUS_TYPE, "Acct-Status-Type",
          RADIUS_ATTR_INT32 },
        { RADIUS_ATTR_ACCT_DELAY_TIME, "Acct-Delay-Time", RADIUS_ATTR_INT32 },
        { RADIUS_ATTR_ACCT_INPUT_OCTETS, "Acct-Input-Octets",
          RADIUS_ATTR_INT32 },
        { RADIUS_ATTR_ACCT_OUTPUT_OCTETS, "Acct-Output-Octets",
          RADIUS_ATTR_INT32 },
        { RADIUS_ATTR_ACCT_SESSION_ID, "Acct-Session-Id", RADIUS_ATTR_TEXT },
        { RADIUS_ATTR_ACCT_AUTHENTIC, "Acct-Authentic", RADIUS_ATTR_INT32 },
        { RADIUS_ATTR_ACCT_SESSION_TIME, "Acct-Session-Time",
          RADIUS_ATTR_INT32 },
        { RADIUS_ATTR_ACCT_INPUT_PACKETS, "Acct-Input-Packets",
          RADIUS_ATTR_INT32 },
        { RADIUS_ATTR_ACCT_OUTPUT_PACKETS, "Acct-Output-Packets",
          RADIUS_ATTR_INT32 },
        { RADIUS_ATTR_ACCT_TERMINATE_CAUSE, "Acct-Terminate-Cause",
          RADIUS_ATTR_INT32 },
        { RADIUS_ATTR_ACCT_MULTI_SESSION_ID, "Acct-Multi-Session-Id",
          RADIUS_ATTR_TEXT },
        { RADIUS_ATTR_ACCT_LINK_COUNT, "Acct-Link-Count", RADIUS_ATTR_INT32 },
        { RADIUS_ATTR_ACCT_INPUT_GIGAWORDS, "Acct-Input-Gigawords", 
          RADIUS_ATTR_INT32 },
        { RADIUS_ATTR_ACCT_OUTPUT_GIGAWORDS, "Acct-Output-Gigawords",
          RADIUS_ATTR_INT32 },
        { RADIUS_ATTR_EVENT_TIMESTAMP, "Event-Timestamp",
          RADIUS_ATTR_INT32 },
        { RADIUS_ATTR_NAS_PORT_TYPE, "NAS-Port-Type", RADIUS_ATTR_INT32 },
        { RADIUS_ATTR_TUNNEL_TYPE, "Tunnel-Type", RADIUS_ATTR_HEXDUMP },
        { RADIUS_ATTR_TUNNEL_MEDIUM_TYPE, "Tunnel-Medium-Type",
          RADIUS_ATTR_HEXDUMP },
        { RADIUS_ATTR_CONNECT_INFO, "Connect-Info", RADIUS_ATTR_TEXT },
        { RADIUS_ATTR_EAP_MESSAGE, "EAP-Message", RADIUS_ATTR_UNDIST },
        { RADIUS_ATTR_MESSAGE_AUTHENTICATOR, "Message-Authenticator",
          RADIUS_ATTR_UNDIST },
        { RADIUS_ATTR_TUNNEL_PRIVATE_GROUP_ID, "Tunnel-Private-Group-Id",
          RADIUS_ATTR_HEXDUMP },
        { RADIUS_ATTR_ACCT_INTERIM_INTERVAL, "Acct-Interim-Interval",
          RADIUS_ATTR_INT32 },
        { RADIUS_ATTR_CHARGEABLE_USER_IDENTITY, "Chargable-User-Identity",
          RADIUS_ATTR_TEXT },
        { RADIUS_ATTR_NAS_IPV6_ADDRESS, "NAS-IPv6-Address", RADIUS_ATTR_IPV6 },
};
#define RADIUS_ATTRS (sizeof(radius_attrs) / sizeof(radius_attrs[0]))


static struct radius_attr_type *radius_get_attr_type(u8 type)
{
        size_t i;

        for (i = 0; i < RADIUS_ATTRS; i++) {
                if (type == radius_attrs[i].type)
                        return &radius_attrs[i];
        }

        return NULL;
}


static void print_char(char c)
{
        if (c >= 32 && c < 127)
                printf("%c", c);
        else
                printf("<%02x>", c);
}


static void radius_msg_dump_attr(struct radius_attr_hdr *hdr)
{
        struct radius_attr_type *attr;
        int i, len;
        unsigned char *pos;

        attr = radius_get_attr_type(hdr->type);

        printf("   Attribute %d (%s) length=%d\n",
               hdr->type, attr ? attr->name : "?Unknown?", hdr->length);

        if (attr == NULL)
                return;

        len = hdr->length - sizeof(struct radius_attr_hdr);
        pos = (unsigned char *) (hdr + 1);

        switch (attr->data_type) {
        case RADIUS_ATTR_TEXT:
                printf("      Value: '");
                for (i = 0; i < len; i++)
                        print_char(pos[i]);
                printf("'\n");
                break;

        case RADIUS_ATTR_IP:
                if (len == 4) {
                        struct in_addr addr;
                        os_memcpy(&addr, pos, 4);
                        printf("      Value: %s\n", inet_ntoa(addr));
                } else
                        printf("      Invalid IP address length %d\n", len);
                break;

#ifdef CONFIG_IPV6
        case RADIUS_ATTR_IPV6:
                if (len == 16) {
                        char buf[128];
                        const char *atxt;
                        struct in6_addr *addr = (struct in6_addr *) pos;
                        atxt = inet_ntop(AF_INET6, addr, buf, sizeof(buf));
                        printf("      Value: %s\n", atxt ? atxt : "?");
                } else
                        printf("      Invalid IPv6 address length %d\n", len);
                break;
#endif /* CONFIG_IPV6 */

        case RADIUS_ATTR_HEXDUMP:
        case RADIUS_ATTR_UNDIST:
                printf("      Value:");
                for (i = 0; i < len; i++)
                        printf(" %02x", pos[i]);
                printf("\n");
                break;

        case RADIUS_ATTR_INT32:
                if (len == 4)
                        printf("      Value: %u\n", WPA_GET_BE32(pos));
                else
                        printf("      Invalid INT32 length %d\n", len);
                break;

        default:
                break;
        }
}


void radius_msg_dump(struct radius_msg *msg)
{
        size_t i;

        printf("RADIUS message: code=%d (%s) identifier=%d length=%d\n",
               msg->hdr->code, radius_code_string(msg->hdr->code),
               msg->hdr->identifier, ntohs(msg->hdr->length));

        for (i = 0; i < msg->attr_used; i++) {
                struct radius_attr_hdr *attr = radius_get_attr_hdr(msg, i);
                radius_msg_dump_attr(attr);
        }
}


int radius_msg_finish(struct radius_msg *msg, const u8 *secret,
                      size_t secret_len)
{
        if (secret) {
                u8 auth[MD5_MAC_LEN];
                struct radius_attr_hdr *attr;

                os_memset(auth, 0, MD5_MAC_LEN);
                attr = radius_msg_add_attr(msg,
                                           RADIUS_ATTR_MESSAGE_AUTHENTICATOR,
                                           auth, MD5_MAC_LEN);
                if (attr == NULL) {
                        printf("WARNING: Could not add "
                               "Message-Authenticator\n");
                        return -1;
                }
                msg->hdr->length = htons(msg->buf_used);
                hmac_md5(secret, secret_len, msg->buf, msg->buf_used,
                         (u8 *) (attr + 1));
        } else
                msg->hdr->length = htons(msg->buf_used);

        if (msg->buf_used > 0xffff) {
                printf("WARNING: too long RADIUS message (%lu)\n",
                       (unsigned long) msg->buf_used);
                return -1;
        }
        return 0;
}


int radius_msg_finish_srv(struct radius_msg *msg, const u8 *secret,
                          size_t secret_len, const u8 *req_authenticator)
{
        u8 auth[MD5_MAC_LEN];
        struct radius_attr_hdr *attr;
        const u8 *addr[4];
        size_t len[4];

        os_memset(auth, 0, MD5_MAC_LEN);
        attr = radius_msg_add_attr(msg, RADIUS_ATTR_MESSAGE_AUTHENTICATOR,
                                   auth, MD5_MAC_LEN);
        if (attr == NULL) {
                printf("WARNING: Could not add Message-Authenticator\n");
                return -1;
        }
        msg->hdr->length = htons(msg->buf_used);
        os_memcpy(msg->hdr->authenticator, req_authenticator,
                  sizeof(msg->hdr->authenticator));
        hmac_md5(secret, secret_len, msg->buf, msg->buf_used,
                 (u8 *) (attr + 1));

        /* ResponseAuth = MD5(Code+ID+Length+RequestAuth+Attributes+Secret) */
        addr[0] = (u8 *) msg->hdr;
        len[0] = 1 + 1 + 2;
        addr[1] = req_authenticator;
        len[1] = MD5_MAC_LEN;
        addr[2] = (u8 *) (msg->hdr + 1);
        len[2] = msg->buf_used - sizeof(*msg->hdr);
        addr[3] = secret;
        len[3] = secret_len;
        md5_vector(4, addr, len, msg->hdr->authenticator);

        if (msg->buf_used > 0xffff) {
                printf("WARNING: too long RADIUS message (%lu)\n",
                       (unsigned long) msg->buf_used);
                return -1;
        }
        return 0;
}


void radius_msg_finish_acct(struct radius_msg *msg, const u8 *secret,
                            size_t secret_len)
{
        const u8 *addr[2];
        size_t len[2];

        msg->hdr->length = htons(msg->buf_used);
        os_memset(msg->hdr->authenticator, 0, MD5_MAC_LEN);
        addr[0] = msg->buf;
        len[0] = msg->buf_used;
        addr[1] = secret;
        len[1] = secret_len;
        md5_vector(2, addr, len, msg->hdr->authenticator);

        if (msg->buf_used > 0xffff) {
                printf("WARNING: too long RADIUS messages (%lu)\n",
                       (unsigned long) msg->buf_used);
        }
}


static int radius_msg_add_attr_to_array(struct radius_msg *msg,
                                        struct radius_attr_hdr *attr)
{
        if (msg->attr_used >= msg->attr_size) {
                size_t *nattr_pos;
                int nlen = msg->attr_size * 2;

                nattr_pos = os_realloc(msg->attr_pos,
                                       nlen * sizeof(*msg->attr_pos));
                if (nattr_pos == NULL)
                        return -1;

                msg->attr_pos = nattr_pos;
                msg->attr_size = nlen;
        }

        msg->attr_pos[msg->attr_used++] = (unsigned char *) attr - msg->buf;

        return 0;
}


struct radius_attr_hdr *radius_msg_add_attr(struct radius_msg *msg, u8 type,
                                            const u8 *data, size_t data_len)
{
        size_t buf_needed;
        struct radius_attr_hdr *attr;

        if (data_len > RADIUS_MAX_ATTR_LEN) {
                printf("radius_msg_add_attr: too long attribute (%lu bytes)\n",
                       (unsigned long) data_len);
                return NULL;
        }

        buf_needed = msg->buf_used + sizeof(*attr) + data_len;

        if (msg->buf_size < buf_needed) {
                /* allocate more space for message buffer */
                unsigned char *nbuf;
                size_t nlen = msg->buf_size;

                while (nlen < buf_needed)
                        nlen *= 2;
                nbuf = os_realloc(msg->buf, nlen);
                if (nbuf == NULL)
                        return NULL;
                msg->buf = nbuf;
                msg->hdr = (struct radius_hdr *) msg->buf;
                os_memset(msg->buf + msg->buf_size, 0, nlen - msg->buf_size);
                msg->buf_size = nlen;
        }

        attr = (struct radius_attr_hdr *) (msg->buf + msg->buf_used);
        attr->type = type;
        attr->length = sizeof(*attr) + data_len;
        if (data_len > 0)
                os_memcpy(attr + 1, data, data_len);

        msg->buf_used += sizeof(*attr) + data_len;

        if (radius_msg_add_attr_to_array(msg, attr))
                return NULL;

        return attr;
}


struct radius_msg *radius_msg_parse(const u8 *data, size_t len)
{
        struct radius_msg *msg;
        struct radius_hdr *hdr;
        struct radius_attr_hdr *attr;
        size_t msg_len;
        unsigned char *pos, *end;

        if (data == NULL || len < sizeof(*hdr))
                return NULL;

        hdr = (struct radius_hdr *) data;

        msg_len = ntohs(hdr->length);
        if (msg_len < sizeof(*hdr) || msg_len > len) {
                printf("Invalid RADIUS message length\n");
                return NULL;
        }

        if (msg_len < len) {
                printf("Ignored %lu extra bytes after RADIUS message\n",
                       (unsigned long) len - msg_len);
        }

        msg = os_malloc(sizeof(*msg));
        if (msg == NULL)
                return NULL;

        if (radius_msg_initialize(msg, msg_len)) {
                os_free(msg);
                return NULL;
        }

        os_memcpy(msg->buf, data, msg_len);
        msg->buf_size = msg->buf_used = msg_len;

        /* parse attributes */
        pos = (unsigned char *) (msg->hdr + 1);
        end = msg->buf + msg->buf_used;
        while (pos < end) {
                if ((size_t) (end - pos) < sizeof(*attr))
                        goto fail;

                attr = (struct radius_attr_hdr *) pos;

                if (pos + attr->length > end || attr->length < sizeof(*attr))
                        goto fail;

                /* TODO: check that attr->length is suitable for attr->type */

                if (radius_msg_add_attr_to_array(msg, attr))
                        goto fail;

                pos += attr->length;
        }

        return msg;

 fail:
        radius_msg_free(msg);
        os_free(msg);
        return NULL;
}


int radius_msg_add_eap(struct radius_msg *msg, const u8 *data, size_t data_len)
{
        const u8 *pos = data;
        size_t left = data_len;

        while (left > 0) {
                int len;
                if (left > RADIUS_MAX_ATTR_LEN)
                        len = RADIUS_MAX_ATTR_LEN;
                else
                        len = left;

                if (!radius_msg_add_attr(msg, RADIUS_ATTR_EAP_MESSAGE,
                                         pos, len))
                        return 0;

                pos += len;
                left -= len;
        }

        return 1;
}


u8 *radius_msg_get_eap(struct radius_msg *msg, size_t *eap_len)
{
        u8 *eap, *pos;
        size_t len, i;
        struct radius_attr_hdr *attr;

        if (msg == NULL)
                return NULL;

        len = 0;
        for (i = 0; i < msg->attr_used; i++) {
                attr = radius_get_attr_hdr(msg, i);
                if (attr->type == RADIUS_ATTR_EAP_MESSAGE)
                        len += attr->length - sizeof(struct radius_attr_hdr);
        }

        if (len == 0)
                return NULL;

        eap = os_malloc(len);
        if (eap == NULL)
                return NULL;

        pos = eap;
        for (i = 0; i < msg->attr_used; i++) {
                attr = radius_get_attr_hdr(msg, i);
                if (attr->type == RADIUS_ATTR_EAP_MESSAGE) {
                        int flen = attr->length - sizeof(*attr);
                        os_memcpy(pos, attr + 1, flen);
                        pos += flen;
                }
        }

        if (eap_len)
                *eap_len = len;

        return eap;
}


int radius_msg_verify_msg_auth(struct radius_msg *msg, const u8 *secret,
                               size_t secret_len, const u8 *req_auth)
{
        u8 auth[MD5_MAC_LEN], orig[MD5_MAC_LEN];
        u8 orig_authenticator[16];
        struct radius_attr_hdr *attr = NULL, *tmp;
        size_t i;

        for (i = 0; i < msg->attr_used; i++) {
                tmp = radius_get_attr_hdr(msg, i);
                if (tmp->type == RADIUS_ATTR_MESSAGE_AUTHENTICATOR) {
                        if (attr != NULL) {
                                printf("Multiple Message-Authenticator "
                                       "attributes in RADIUS message\n");
                                return 1;
                        }
                        attr = tmp;
                }
        }

        if (attr == NULL) {
                printf("No Message-Authenticator attribute found\n");
                return 1;
        }

        os_memcpy(orig, attr + 1, MD5_MAC_LEN);
        os_memset(attr + 1, 0, MD5_MAC_LEN);
        if (req_auth) {
                os_memcpy(orig_authenticator, msg->hdr->authenticator,
                          sizeof(orig_authenticator));
                os_memcpy(msg->hdr->authenticator, req_auth,
                          sizeof(msg->hdr->authenticator));
        }
        hmac_md5(secret, secret_len, msg->buf, msg->buf_used, auth);
        os_memcpy(attr + 1, orig, MD5_MAC_LEN);
        if (req_auth) {
                os_memcpy(msg->hdr->authenticator, orig_authenticator,
                          sizeof(orig_authenticator));
        }

        if (os_memcmp(orig, auth, MD5_MAC_LEN) != 0) {
                printf("Invalid Message-Authenticator!\n");
                return 1;
        }

        return 0;
}


int radius_msg_verify(struct radius_msg *msg, const u8 *secret,
                      size_t secret_len, struct radius_msg *sent_msg, int auth)
{
        const u8 *addr[4];
        size_t len[4];
        u8 hash[MD5_MAC_LEN];

        if (sent_msg == NULL) {
                printf("No matching Access-Request message found\n");
                return 1;
        }

        if (auth &&
            radius_msg_verify_msg_auth(msg, secret, secret_len,
                                       sent_msg->hdr->authenticator)) {
                return 1;
        }

        /* ResponseAuth = MD5(Code+ID+Length+RequestAuth+Attributes+Secret) */
        addr[0] = (u8 *) msg->hdr;
        len[0] = 1 + 1 + 2;
        addr[1] = sent_msg->hdr->authenticator;
        len[1] = MD5_MAC_LEN;
        addr[2] = (u8 *) (msg->hdr + 1);
        len[2] = msg->buf_used - sizeof(*msg->hdr);
        addr[3] = secret;
        len[3] = secret_len;
        md5_vector(4, addr, len, hash);
        if (os_memcmp(hash, msg->hdr->authenticator, MD5_MAC_LEN) != 0) {
                printf("Response Authenticator invalid!\n");
                return 1;
        }

        return 0;
}


int radius_msg_copy_attr(struct radius_msg *dst, struct radius_msg *src,
                         u8 type)
{
        struct radius_attr_hdr *attr;
        size_t i;
        int count = 0;

        for (i = 0; i < src->attr_used; i++) {
                attr = radius_get_attr_hdr(src, i);
                if (attr->type == type) {
                        if (!radius_msg_add_attr(dst, type, (u8 *) (attr + 1),
                                                 attr->length - sizeof(*attr)))
                                return -1;
                        count++;
                }
        }

        return count;
}


/* Create Request Authenticator. The value should be unique over the lifetime
 * of the shared secret between authenticator and authentication server.
 * Use one-way MD5 hash calculated from current timestamp and some data given
 * by the caller. */
void radius_msg_make_authenticator(struct radius_msg *msg,
                                   const u8 *data, size_t len)
{
        struct os_time tv;
        long int l;
        const u8 *addr[3];
        size_t elen[3];

        os_get_time(&tv);
        l = os_random();
        addr[0] = (u8 *) &tv;
        elen[0] = sizeof(tv);
        addr[1] = data;
        elen[1] = len;
        addr[2] = (u8 *) &l;
        elen[2] = sizeof(l);
        md5_vector(3, addr, elen, msg->hdr->authenticator);
}


/* Get Vendor-specific RADIUS Attribute from a parsed RADIUS message.
 * Returns the Attribute payload and sets alen to indicate the length of the
 * payload if a vendor attribute with subtype is found, otherwise returns NULL.
 * The returned payload is allocated with os_malloc() and caller must free it
 * by calling os_free().
 */
static u8 *radius_msg_get_vendor_attr(struct radius_msg *msg, u32 vendor,
                                      u8 subtype, size_t *alen)
{
        u8 *data, *pos;
        size_t i, len;

        if (msg == NULL)
                return NULL;

        for (i = 0; i < msg->attr_used; i++) {
                struct radius_attr_hdr *attr = radius_get_attr_hdr(msg, i);
                size_t left;
                u32 vendor_id;
                struct radius_attr_vendor *vhdr;

                if (attr->type != RADIUS_ATTR_VENDOR_SPECIFIC)
                        continue;

                left = attr->length - sizeof(*attr);
                if (left < 4)
                        continue;

                pos = (u8 *) (attr + 1);

                os_memcpy(&vendor_id, pos, 4);
                pos += 4;
                left -= 4;

                if (ntohl(vendor_id) != vendor)
                        continue;

                while (left >= sizeof(*vhdr)) {
                        vhdr = (struct radius_attr_vendor *) pos;
                        if (vhdr->vendor_length > left ||
                            vhdr->vendor_length < sizeof(*vhdr)) {
                                left = 0;
                                break;
                        }
                        if (vhdr->vendor_type != subtype) {
                                pos += vhdr->vendor_length;
                                left -= vhdr->vendor_length;
                                continue;
                        }

                        len = vhdr->vendor_length - sizeof(*vhdr);
                        data = os_malloc(len);
                        if (data == NULL)
                                return NULL;
                        os_memcpy(data, pos + sizeof(*vhdr), len);
                        if (alen)
                                *alen = len;
                        return data;
                }
        }

        return NULL;
}


static u8 * decrypt_ms_key(const u8 *key, size_t len,
                           const u8 *req_authenticator,
                           const u8 *secret, size_t secret_len, size_t *reslen)
{
        u8 *plain, *ppos, *res;
        const u8 *pos;
        size_t left, plen;
        u8 hash[MD5_MAC_LEN];
        int i, first = 1;
        const u8 *addr[3];
        size_t elen[3];

        /* key: 16-bit salt followed by encrypted key info */

        if (len < 2 + 16)
                return NULL;

        pos = key + 2;
        left = len - 2;
        if (left % 16) {
                printf("Invalid ms key len %lu\n", (unsigned long) left);
                return NULL;
        }

        plen = left;
        ppos = plain = os_malloc(plen);
        if (plain == NULL)
                return NULL;
        plain[0] = 0;

        while (left > 0) {
                /* b(1) = MD5(Secret + Request-Authenticator + Salt)
                 * b(i) = MD5(Secret + c(i - 1)) for i > 1 */

                addr[0] = secret;
                elen[0] = secret_len;
                if (first) {
                        addr[1] = req_authenticator;
                        elen[1] = MD5_MAC_LEN;
                        addr[2] = key;
                        elen[2] = 2; /* Salt */
                } else {
                        addr[1] = pos - MD5_MAC_LEN;
                        elen[1] = MD5_MAC_LEN;
                }
                md5_vector(first ? 3 : 2, addr, elen, hash);
                first = 0;

                for (i = 0; i < MD5_MAC_LEN; i++)
                        *ppos++ = *pos++ ^ hash[i];
                left -= MD5_MAC_LEN;
        }

        if (plain[0] == 0 || plain[0] > plen - 1) {
                printf("Failed to decrypt MPPE key\n");
                os_free(plain);
                return NULL;
        }

        res = os_malloc(plain[0]);
        if (res == NULL) {
                os_free(plain);
                return NULL;
        }
        os_memcpy(res, plain + 1, plain[0]);
        if (reslen)
                *reslen = plain[0];
        os_free(plain);
        return res;
}


static void encrypt_ms_key(const u8 *key, size_t key_len, u16 salt,
                           const u8 *req_authenticator,
                           const u8 *secret, size_t secret_len,
                           u8 *ebuf, size_t *elen)
{
        int i, len, first = 1;
        u8 hash[MD5_MAC_LEN], saltbuf[2], *pos;
        const u8 *addr[3];
        size_t _len[3];

        WPA_PUT_BE16(saltbuf, salt);

        len = 1 + key_len;
        if (len & 0x0f) {
                len = (len & 0xf0) + 16;
        }
        os_memset(ebuf, 0, len);
        ebuf[0] = key_len;
        os_memcpy(ebuf + 1, key, key_len);

        *elen = len;

        pos = ebuf;
        while (len > 0) {
                /* b(1) = MD5(Secret + Request-Authenticator + Salt)
                 * b(i) = MD5(Secret + c(i - 1)) for i > 1 */
                addr[0] = secret;
                _len[0] = secret_len;
                if (first) {
                        addr[1] = req_authenticator;
                        _len[1] = MD5_MAC_LEN;
                        addr[2] = saltbuf;
                        _len[2] = sizeof(saltbuf);
                } else {
                        addr[1] = pos - MD5_MAC_LEN;
                        _len[1] = MD5_MAC_LEN;
                }
                md5_vector(first ? 3 : 2, addr, _len, hash);
                first = 0;

                for (i = 0; i < MD5_MAC_LEN; i++)
                        *pos++ ^= hash[i];

                len -= MD5_MAC_LEN;
        }
}


struct radius_ms_mppe_keys *
radius_msg_get_ms_keys(struct radius_msg *msg, struct radius_msg *sent_msg,
                       const u8 *secret, size_t secret_len)
{
        u8 *key;
        size_t keylen;
        struct radius_ms_mppe_keys *keys;

        if (msg == NULL || sent_msg == NULL)
                return NULL;

        keys = os_zalloc(sizeof(*keys));
        if (keys == NULL)
                return NULL;

        key = radius_msg_get_vendor_attr(msg, RADIUS_VENDOR_ID_MICROSOFT,
                                         RADIUS_VENDOR_ATTR_MS_MPPE_SEND_KEY,
                                         &keylen);
        if (key) {
                keys->send = decrypt_ms_key(key, keylen,
                                            sent_msg->hdr->authenticator,
                                            secret, secret_len,
                                            &keys->send_len);
                os_free(key);
        }

        key = radius_msg_get_vendor_attr(msg, RADIUS_VENDOR_ID_MICROSOFT,
                                         RADIUS_VENDOR_ATTR_MS_MPPE_RECV_KEY,
                                         &keylen);
        if (key) {
                keys->recv = decrypt_ms_key(key, keylen,
                                            sent_msg->hdr->authenticator,
                                            secret, secret_len,
                                            &keys->recv_len);
                os_free(key);
        }

        return keys;
}


struct radius_ms_mppe_keys *
radius_msg_get_cisco_keys(struct radius_msg *msg, struct radius_msg *sent_msg,
                          const u8 *secret, size_t secret_len)
{
        u8 *key;
        size_t keylen;
        struct radius_ms_mppe_keys *keys;

        if (msg == NULL || sent_msg == NULL)
                return NULL;

        keys = os_zalloc(sizeof(*keys));
        if (keys == NULL)
                return NULL;

        key = radius_msg_get_vendor_attr(msg, RADIUS_VENDOR_ID_CISCO,
                                         RADIUS_CISCO_AV_PAIR, &keylen);
        if (key && keylen == 51 &&
            os_memcmp(key, "leap:session-key=", 17) == 0) {
                keys->recv = decrypt_ms_key(key + 17, keylen - 17,
                                            sent_msg->hdr->authenticator,
                                            secret, secret_len,
                                            &keys->recv_len);
        }
        os_free(key);

        return keys;
}


int radius_msg_add_mppe_keys(struct radius_msg *msg,
                             const u8 *req_authenticator,
                             const u8 *secret, size_t secret_len,
                             const u8 *send_key, size_t send_key_len,
                             const u8 *recv_key, size_t recv_key_len)
{
        struct radius_attr_hdr *attr;
        u32 vendor_id = htonl(RADIUS_VENDOR_ID_MICROSOFT);
        u8 *buf;
        struct radius_attr_vendor *vhdr;
        u8 *pos;
        size_t elen;
        int hlen;
        u16 salt;

        hlen = sizeof(vendor_id) + sizeof(*vhdr) + 2;

        /* MS-MPPE-Send-Key */
        buf = os_malloc(hlen + send_key_len + 16);
        if (buf == NULL) {
                return 0;
        }
        pos = buf;
        os_memcpy(pos, &vendor_id, sizeof(vendor_id));
        pos += sizeof(vendor_id);
        vhdr = (struct radius_attr_vendor *) pos;
        vhdr->vendor_type = RADIUS_VENDOR_ATTR_MS_MPPE_SEND_KEY;
        pos = (u8 *) (vhdr + 1);
        salt = os_random() | 0x8000;
        WPA_PUT_BE16(pos, salt);
        pos += 2;
        encrypt_ms_key(send_key, send_key_len, salt, req_authenticator, secret,
                       secret_len, pos, &elen);
        vhdr->vendor_length = hlen + elen - sizeof(vendor_id);

        attr = radius_msg_add_attr(msg, RADIUS_ATTR_VENDOR_SPECIFIC,
                                   buf, hlen + elen);
        os_free(buf);
        if (attr == NULL) {
                return 0;
        }

        /* MS-MPPE-Recv-Key */
        buf = os_malloc(hlen + send_key_len + 16);
        if (buf == NULL) {
                return 0;
        }
        pos = buf;
        os_memcpy(pos, &vendor_id, sizeof(vendor_id));
        pos += sizeof(vendor_id);
        vhdr = (struct radius_attr_vendor *) pos;
        vhdr->vendor_type = RADIUS_VENDOR_ATTR_MS_MPPE_RECV_KEY;
        pos = (u8 *) (vhdr + 1);
        salt ^= 1;
        WPA_PUT_BE16(pos, salt);
        pos += 2;
        encrypt_ms_key(recv_key, recv_key_len, salt, req_authenticator, secret,
                       secret_len, pos, &elen);
        vhdr->vendor_length = hlen + elen - sizeof(vendor_id);

        attr = radius_msg_add_attr(msg, RADIUS_ATTR_VENDOR_SPECIFIC,
                                   buf, hlen + elen);
        os_free(buf);
        if (attr == NULL) {
                return 0;
        }

        return 1;
}


/* Add User-Password attribute to a RADIUS message and encrypt it as specified
 * in RFC 2865, Chap. 5.2 */
struct radius_attr_hdr *
radius_msg_add_attr_user_password(struct radius_msg *msg,
                                  const u8 *data, size_t data_len,
                                  const u8 *secret, size_t secret_len)
{
        u8 buf[128];
        int padlen, i;
        size_t buf_len, pos;
        const u8 *addr[2];
        size_t len[2];
        u8 hash[16];

        if (data_len > 128)
                return NULL;

        os_memcpy(buf, data, data_len);
        buf_len = data_len;

        padlen = data_len % 16;
        if (padlen) {
                padlen = 16 - padlen;
                os_memset(buf + data_len, 0, padlen);
                buf_len += padlen;
        }

        addr[0] = secret;
        len[0] = secret_len;
        addr[1] = msg->hdr->authenticator;
        len[1] = 16;
        md5_vector(2, addr, len, hash);

        for (i = 0; i < 16; i++)
                buf[i] ^= hash[i];
        pos = 16;

        while (pos < buf_len) {
                addr[0] = secret;
                len[0] = secret_len;
                addr[1] = &buf[pos - 16];
                len[1] = 16;
                md5_vector(2, addr, len, hash);

                for (i = 0; i < 16; i++)
                        buf[pos + i] ^= hash[i];

                pos += 16;
        }

        return radius_msg_add_attr(msg, RADIUS_ATTR_USER_PASSWORD,
                                   buf, buf_len);
}


int radius_msg_get_attr(struct radius_msg *msg, u8 type, u8 *buf, size_t len)
{
        struct radius_attr_hdr *attr = NULL, *tmp;
        size_t i, dlen;

        for (i = 0; i < msg->attr_used; i++) {
                tmp = radius_get_attr_hdr(msg, i);
                if (tmp->type == type) {
                        attr = tmp;
                        break;
                }
        }

        if (!attr)
                return -1;

        dlen = attr->length - sizeof(*attr);
        if (buf)
                os_memcpy(buf, (attr + 1), dlen > len ? len : dlen);
        return dlen;
}


int radius_msg_get_attr_ptr(struct radius_msg *msg, u8 type, u8 **buf,
                            size_t *len, const u8 *start)
{
        size_t i;
        struct radius_attr_hdr *attr = NULL, *tmp;

        for (i = 0; i < msg->attr_used; i++) {
                tmp = radius_get_attr_hdr(msg, i);
                if (tmp->type == type &&
                    (start == NULL || (u8 *) tmp > start)) {
                        attr = tmp;
                        break;
                }
        }

        if (!attr)
                return -1;

        *buf = (u8 *) (attr + 1);
        *len = attr->length - sizeof(*attr);
        return 0;
}


int radius_msg_count_attr(struct radius_msg *msg, u8 type, int min_len)
{
        size_t i;
        int count;

        for (count = 0, i = 0; i < msg->attr_used; i++) {
                struct radius_attr_hdr *attr = radius_get_attr_hdr(msg, i);
                if (attr->type == type &&
                    attr->length >= sizeof(struct radius_attr_hdr) + min_len)
                        count++;
        }

        return count;
}


struct radius_tunnel_attrs {
        int tag_used;
        int type; /* Tunnel-Type */
        int medium_type; /* Tunnel-Medium-Type */
        int vlanid;
};


/**
 * radius_msg_get_vlanid - Parse RADIUS attributes for VLAN tunnel information
 * @msg: RADIUS message
 * Returns: VLAN ID for the first tunnel configuration of -1 if none is found
 */
int radius_msg_get_vlanid(struct radius_msg *msg)
{
        struct radius_tunnel_attrs tunnel[RADIUS_TUNNEL_TAGS], *tun;
        size_t i;
        struct radius_attr_hdr *attr = NULL;
        const u8 *data;
        char buf[10];
        size_t dlen;

        os_memset(&tunnel, 0, sizeof(tunnel));

        for (i = 0; i < msg->attr_used; i++) {
                attr = radius_get_attr_hdr(msg, i);
                data = (const u8 *) (attr + 1);
                dlen = attr->length - sizeof(*attr);
                if (attr->length < 3)
                        continue;
                if (data[0] >= RADIUS_TUNNEL_TAGS)
                        tun = &tunnel[0];
                else
                        tun = &tunnel[data[0]];

                switch (attr->type) {
                case RADIUS_ATTR_TUNNEL_TYPE:
                        if (attr->length != 6)
                                break;
                        tun->tag_used++;
                        tun->type = WPA_GET_BE24(data + 1);
                        break;
                case RADIUS_ATTR_TUNNEL_MEDIUM_TYPE:
                        if (attr->length != 6)
                                break;
                        tun->tag_used++;
                        tun->medium_type = WPA_GET_BE24(data + 1);
                        break;
                case RADIUS_ATTR_TUNNEL_PRIVATE_GROUP_ID:
                        if (data[0] < RADIUS_TUNNEL_TAGS) {
                                data++;
                                dlen--;
                        }
                        if (dlen >= sizeof(buf))
                                break;
                        os_memcpy(buf, data, dlen);
                        buf[dlen] = '\0';
                        tun->tag_used++;
                        tun->vlanid = atoi(buf);
                        break;
                }
        }

        for (i = 0; i < RADIUS_TUNNEL_TAGS; i++) {
                tun = &tunnel[i];
                if (tun->tag_used &&
                    tun->type == RADIUS_TUNNEL_TYPE_VLAN &&
                    tun->medium_type == RADIUS_TUNNEL_MEDIUM_TYPE_802 &&
                    tun->vlanid > 0)
                        return tun->vlanid;
        }

        return -1;
}
